Hello, I'm steelesaber13. I've been playing League of Legends for about two years now, as Skarthe on the NA server. I'm not the best player - my mechanics definitely need some work - but I feel that I understand some champions enough that I can at least add my knowledge to the collective base of it. On top of that, I found the other guides for this particular champion to be less than satisfactory, so here's my guide for the champion Tristana.

This guide is intended for Summoner's Rift, but can also be applied with some success to any other game mode. I'll be making a couple of assumptions for a lot of the guide: mainly I'll be assuming that Tristana is being played as an AD carry in a typical AD-support duo bottom lane.

There are a few terms that I use repeatedly throughout this guide, and I'd like to go on and give them an internally-consistent definition.

AD Carry: A champion who relies primarily on auto-attacks to deal damage into the late game. These champions are usually paired with a support and sent to the bottom lane, and they usually have poor early-game damage but excellent late-game damage. Tristana is usually played as an AD carry.

AP Carry: A champion who relies primarily on abilities that scale with Ability Power to deal damage. These champions vary wildly in their strength, but usually hit their stride around the mid-game, while falling off in damage later on as AD carries become stronger. These champions are usually sent to the middle lane. Tristana can be played as one of these in a pinch.

Laning Phase: The portion of the game during which people generally keep to their lanes and don't group up much except to gank. This usually ends around the time towers start to fall.

Early Game: Generally coincides with the laning phase. Often starts to end either as towers fall or as champions start to complete their first or second major items.

Mid Game: The phase immediately after the early game. Generally lasts until champions have three or four major items completed, hit high levels, or are starting to force major objectives like Baron Nashor.

Late Game: The final phase of the game. This is when champions start to max out their levels and their builds, reaching their full end-game potential.

Tristana is a ranged champion who can be played as either an Attack Damage or Ability Power based carry. For purposes of this guide, I'll mostly be focusing on the traditional AD style, but I will touch upon the AP style as well later in the guide.

Tristana is available to nearly every player due to being available for free via Riot Games's Facebook promotion. She has a good early game and a great late game, and is not difficult to play. She brings decent utility to the table with her heal reduction, escape tool, and displacement ability. She also has extremely high damage with her 90% attack speed steroid, and very high range to back it up in the late game. In conjunction with her escape ability, this makes her both an extremely strong and very safe champion once champions start hitting higher levels.

However, Tristana has a sort of U-shaped power curve. She is strong in the early game and very strong in the late game, but her mid game is rather poor, since her range will not be extremely high and she won't have the items to outdamage her opponents yet.

Tristana's passive, which increases her range by 9 per level, is part of what makes her an extremely strong late-game champion. Her starting range of 550 is only average, but her level 18 range of 703 is the third-highest in the game, behind Kog'Maw's 710 while using Bio-Arcane Barrage and Twitch's 850 while using his ultimate. Of these three, Tristana is the only one with a movement ability, making her the safest of the three. Here's an overview of when Tristana begins to outrange other AD carries.

Tristana's Rapid Fire is the strongest attack speed steroid available to a ranged champion. It is an extremely strong ability in the mid-game and late-game stages, but is arguably her least important ability in the laning phase. As such, it tends to not be skilled until either level 4 or 8, but is then usually her second skill to be maxed.

When it is available, it is usually a good idea to activate Rapid Fire any time you need to deal damage to anything aside from a minion, and even then it can be a good waveclear tool in conjunction with the passive from Explosive Shot. If you expect a teamfight to break out though, it may be a good idea to hold onto Rapid Fire until the fight starts.

W: Rocket Jump

22/20/18/16/14 second cooldown

80 mana cost

900 range

"Tristana fires at the ground to propel herself to target location, dealing 70/115/160/205/250 (+80% Ability Power) magic damage and slowing surrounding units by 60% for 2.5 seconds when she lands. On a champion kill or assist, Rocket Jump's cooldown resets."

Rocket Jump is Tristana's primary escape tool. I take a point in this at either level 1 or 2 depending on my opponents; if they have any kind of grab or hard crowd-control abilities that I expect to have to contend with at level 1 (such as an enemy Blitzcrank, Thresh, or Taric) I will usually take this immediately for safety's sake.

Rocket Jump has good range and is able to clear walls with relative ease. However, it is a somewhat deceptive ability: while it can clear walls and units, you are still treated normally by nearly everything else. This means that abilities and attacks can still hit you in midair, and anything on the ground - Teemo's Noxious Traps, Caitlyn's Yordle Snap-Traps, Nidalee's Bushwhack, etc. - will affect you in midair if you pass over them. Slows, snares, and the like will not stop your jump from finishing (you'll just be slowed or snared when you land) but knock-ups (like Alistar's Pulverize) or displacements (Alistar's Headbutt, Blitzcrank's Rocket Grab, etc.) will interrupt your motion.

Unless you are absolutely certain that doing so will result in a kill, it is generally not recommended to use Rocket Jump to enter a fight. Doing so removes your best chance of escaping enemy aggression and, as such, leaves you highly vulnerable to being torn apart by the enemy team. In laning phase this can be a decent tool for attacking your enemy if you and your support (and jungler, perhaps) are going all-in to kill an enemy champion: the slow is nice, the gap-close is nice, the damage is pretty good, and if you get the kill you can use it again right afterwards to escape, making it a decent diving tool. After laning phase, however, the damage and slow on this ability are almost useless for AD Tristana, since using it for this purpose takes away both your range advantage and your escape. Since you are squishy, this is not a good thing!

Explosive Shot is a very good harass tool in lane, but levelling it can be dangerous depending on your situation: once you put a few points into Explosive Shot, your lane control may suffer greatly since you will push your lane just from last-hitting enemy minions due to the passive effect. If the enemy team is such that pushing your lane is an extreme risk (strong crowd-control and damage in bottom lane, strong jungler ganks), it may be a good idea to put only one or two points into Explosive Shot, or not to skill it at all.

However, in many cases, Explosive Shot is a solid skill to take at level 1 and max first. Explosive Shot essentially gives you Ignite without having to spend a summoner spell on it. This is a very strong tool for dealing with sustain lanes (anything with Soraka, Sona, Taric, Alistar, or Nami supports) or any other enemy champion who has a lot of healing or regeneration abilities (like Dr. Mundo). If you can predict these abilities, try to time your Explosive Shot use to either delay the enemy heals or force them to heal at half effectiveness. Otherwise, try to just keep hitting your lane opponent with Explosive Shot every time it is off cooldown: this damage tends to add up rather quickly, giving you a solid advantage in your lane.

As the game progresses, this ability's damage falls off quite a bit; it is usually not worth casting for damage later in the game, but can still find use due to its heal reduction.

Let me open with this: using this ability for damage tends to be a very bad idea. It does decent damage, but you need to be absolutely certain it will kill the enemy. You need to make sure the enemy's HP is low, their Magic Resist isn't low enough to mitigate the damage, they don't have a shield or heal available, and so on. If you use Buster Shot and any of this is not true, you have probably just sent an easy kill flying away from your team. If the enemy won't die without it and you think it might get a kill, go ahead and try it - it outranges Tristana's auto-attacks until level 18 - but otherwise make absolutelycertain that it will kill the enemy before you cast this ability.

Now that that's out of the way... Buster Shot is a useful displacement ability. It can be used to blow away enemies who are chasing you or your teammates, allowing you to escape and go about your business. If you're feeling ballsy, you can also use it in conjunction with Rocket Jump to send an enemy flying into your team or your turret, but this tends to loop back into "very bad idea" territory if more than one or two enemy champions are present, since then you're a) away from your team and b) close to the enemy team, which usually makes you c) dead. The displacement can also be used to break channelled abilities, like Malzahar's Nether Grasp or Nunu's Absolute Zero. The displacement distance is pretty good: if you're fighting in the jungle, you can often remove an enemy from the fight entirely by Buster Shotting them over a wall.

Tristana's skill order varies by situation. This is the one that I most commonly find myself using:

E: Explosive Shot (1)

W: Rocket Jump (1)

E: Explosive Shot (2)

W: Rocket Jump (2)

E: Explosive Shot (3)

R: Buster Shot (1)

E: Explosive Shot (4)

Q: Rapid Fire (1)

E: Explosive Shot (5)

Q: Rapid Fire (2)

R: Buster Shot (2)

Q: Rapid Fire (3)

Q: Rapid Fire (4)

Q: Rapid Fire (5)

W: Rocket Jump (3)

R: Buster Shot (3)

W: Rocket Jump (4)

W: Rocket Jump (5)

Switching W and E in this order is a very common alteration, either just at levels 1 and 2 (if you're afraid of a jungle invade or something) or throughout the game. If you don't want to push your lane, or if the enemy team is very dangerous (strong gankers, crowd control-heavy bottom lane, roaming mids, whatever) you may want to max W over E for the reduced cooldown on your jump, plus the reduced lane pushing when you last hit. If you want you can also take a point in Q instead of W at level 4, giving you a bit of a leg-up on that ability, but it usually isn't very useful that early in the game since your attacks won't be doing much damage yet.

Flash is considered a must-have on the majority of champions, and Tristana is no exception: the versatility of the spell is just too good to pass up.

Tristana's second summoner spell depends on situation and personal preference. I usually prefer Cleanse or Barrier. Cleanse is extremely good if the enemy team has stuns, attack speed slows, snares, or other status debuffs that you want to be rid of immediately; if I see these on the enemy team or if I am playing blind pick, I will take Cleanse. Otherwise, I will take Barrier for the added protection both during and after the laning phase.

Ignite is a commonly-seen summoner spell, but I do not believe it to be a very good option for Tristana. The small amount of added damage is not usually worth the loss in safety from losing a defensive summoner spell, and Ignite is rather redundant for Tristana in particular due to Explosive Shot already doing more or less the same thing, with an inferior damage type but a much, much shorter cooldown.

Marks: 9x Greater Mark of Attack Damage (0.95 each for a total of 8.5 attack damage)

Seals: 9x Greater Seal of Armor (1.41 each for a total of 13 armor)

Glyphs: 9x Greater Glyph of Scaling Magic Resist (.15 MR/level each for a total of 24 MR at level 18)

Quintessences: 3x Greater Quintessence of Lifesteal (2% each for a total of 6% lifesteal)

This runepage gives you good trading in lane along with solid sustain. The marks can be traded out for armor penetration for a bit of added late-game power, but this makes your laning damage a bit weaker and makes it more difficult to last-hit. Quintessences can also be traded out for attack damage, but that deals a rather rough blow to your early-game sustain and pigeonholes your starting build somewhat.

I generally run a 21/9/0 mastery build on my AD carries. As a quick rundown, for Tristana I take the most of the left side of the Offense tree, sans Expose Weakness, Spell Weaving, and Blade Weaving; those points instead go to Executioner and Dangerous Game. In the Defense tree, I take full points into Block, Unyielding, Recovery, Veteran's Scars, and Juggernaut.

Offense

Double-Edged Sword (1/1) - 1.5% extra damage dealt and taken: This one's personal preference. As an AD carry, you shouldn't usually be in a position to take enough damage such that the 1.5% extra taken outweighs the 1.5% extra dealt. If you're concerned about it, feel free to not take this mastery; the point could go into Expose Weakness to help team damage once you use Explosive Shot.

Fury (4/4) - 5% attack speed: Attack speed is important for every AD carry. The competing options here are cooldown reduction and increased minion damage, which are not as useful for Tristana.

Brute Force (4/4) - +10 attack damage at level 18: Attack damage is another primary stat for AD carries - it's even in the name of the role! The competing options here are ability power and increased ally damage to targets hit with your spells, plus the previous tier.

Martial Mastery (1/1) - +4 attack damage: Decent for early game. Not huge in the lategame, but there aren't a lot of better options: the Offense tree is pretty neatly divided into AD and AP masteries. Plus, you already have the required points into Brute Force; why not?

Executioner (3/3) - +5% damage to enemies under 50% health: This equates to a rather nice damage boost.

Warlord (3/3) - +5% bonus AD: This is extremely nice. Your bonus AD should be pretty high by the late game, so this usually adds up to a pretty fair amount later on. Not great early game though, since your bonus AD there will be low.

Dangerous Game (1/1) - 5% missing health and mana restored on killing a champion: This isn't huge, but it can come in handy in a pinch and it's only one point, plus we already have the points in Executioner.

Frenzy (1/1) - +10% attack speed for 2 seconds after dealing a critical hit: Another very nice one-point mastery. Once you get a Phantom Dancer and Infinity Edge, you should be critting often enough that this just stays active for the entirety of any fight.

Devastating Strikes (3/3) - +6% armor/magic penetration: This is very nice. Not a huge deal early on when enemies don't have high resists, but comes in quite handy later when they do. Tristana gets double duty from this mastery, too, since her abilities are magic damage; her magic damage isn't very relevant by the time this mastery usually is, but still, a bonus is a bonus.

Block (2/2) - Reduces incoming damage from champion basic attacks by 2: Pretty nice in the laning phase, where the enemy ADC and support are likely to want to hit you a fair bit, but have low enough AD to make this reduction significant. This flat -2 damage reduction can add up pretty quickly.

Recovery (2/2) - +2 health regen per 5 seconds: Not a huge amount, but again, it'll add up over time; for reference, this adds 40% to Tristana's level 1 health regen. Not bad.

Unyielding (1/1) - Reduces all incoming damage from champions by 1: This functions basically like a third point in Block, except it also affects spell damage. Not an overhwelming damage reduction by any means, but it can still come in handy early on.

Veteran's Scars (3/3) - +36 health: This is a very nice health boost in lane. 36 health at low levels often equates to taking an extra hit, which can be the difference between life and death more often than one might think.

Juggernaut (1/1) - +3% max health: More health is always good, plus we already have the points in Veteran's Scars. The added health can help keep you alive in a teamfight; can't do damage if you're dead, after all.

Other Options

There aren't many other options in the Offense tree. Points can be removed from Offense and Defense to be put into Utility, however, in order to gain bonuses like lifesteal, decreased summoner spell cooldowns, enhanced potions, movement speed, and others. The page listed here is my personal favorite and pretty common, but it may be worth experimenting with the Utility tree to see if it suits your playstyle.

Typically I take a Warding Totem as my trinket, to help maintain vision control and avoid getting ganked. Aside from that, I usually go one of three starts on Tristana.

Start 1: Doran's Blade, 1x Health Potion

This is a very solid laning start, giving you extra health, damage, and sustain in lane. This is very good in general, since it helps you both deal damage and take it; as such, it's usually the best start. However, I would not suggest taking this start without lifesteal quintessences: your only sustain will be the Doran's Blade, natural health regen, and one potion, which is usually not enough.

Start 2: Longsword, 3x Health Potion

This start helps you get your build going more quickly at the cost of a chunk of health in lane. The longsword can be quickly built into a Vampiric Scepter, giving you very good sustain; the double health potions help you out in that regard as well. You maintain the damage from Doran's Blade and get a bit more of a head start on your build, but your trading isn't as good since you don't have the extra 80 health. This isn't usually the best start, due to the strength of Doran's items in lane; you're likely to get roughed up a bit if your opponent took Doran's Blade and you didn't.

Start 3: Boots of Speed, 4x Health Potion

This old ubiquitous start has fallen out of favor a bit, but is still a workable path. If you want to play conservatively in lane - worried about a lot of damage, ganks, etc. - this may be the way you want to go. The fourth health potion gives you very solid sustain, and boots should give you a mobility advantage over most attackers while still helping you jump-start your build a little bit. However, you practically can't trade damage in lane, since you'll almost certainly take more damage than you deal, and your opponent will have more health to draw from.

Others

Elixir of Fortitude with three health potions is an alright start for getting a quick advantage in lane with added health and AD, but if you don't manage to get a kill with it you've set yourself behind quite a bit. If you really, really love sustain, you can try a Crystalline Flask, but spending that much on sustain is probably overkill and may cost you time on getting your build rolling, especially since you'll get out-traded.

If your jungler wants your help level 1, you should probably go help them. If not, you can still guard tri-brush (blue side) or blue buff ramp (purple side) just to be a good teammate, then go to lane.

Your top priorities in lane should be survival, then farming, then harassing champions. Try to hit Explosive Shot onto the enemies every chance you get if you can afford to; even better if you can pick one specific one of them to target consistently, and better still if that one has poor sustain. Your all-in damage with Rocket Jump (be careful with this) and Explosive Shot is pretty good, so if you get the enemies rather low and you and your support aren't low, you may want to aim for a kill. Don't be afraid to play aggressively if you can afford to.

As Tristana, you will probably be outpushing your lane opponent just by last-hitting minions due to Explosive Shot's passive. If you get in trouble or get ganked, just Rocket Jump away; Flash and other defensive summoners can also be used if necessary. Otherwise, you may be able to take the enemy's turret before too long, which is often seen as a transition into mid-game. If you can take the turret, or if you kill or force out the enemy AD post-6 or so, see if you, your support, and your jungler can take the dragon.

If you didn't start with Boots of Speed, you'll probably want to get them on your first or second trip back to base. Aside from that, it's often best to build a quick Vampiric Scepter and then aim for a B.F. Sword (unless you come back with enough gold to get the B.F. Sword before the Vamp Scepter, in which case that's also an option): your goal here is usually either a Blade of the Ruined King or an Infinity Edge. Bloodthirster is also a possibility.

Bloodthirster will be faster since you'll likely already have the items that build into it, so all you'll need is the 850g combine cost. It gives more attack damage and better sustain via lifesteal. However, the crit chance and added crit damage from Infinity Edge gives it superior overall damage. I usually take Infinity Edge first on Tristana, since the overall damage is more valuable than the raw attack damage, but it often comes down to personal preference.

Blade of the Ruined King is a pretty good item when you need sustain and extra self-peel. It also can be gotten earlier than Infinity Edge can. If you go Blade of the Ruined King, you usually don't want a Bloodthirster, as you'll already have enough lifesteal; instead, you'll build to Infinity Edge after. Going Blade of the Ruined King before Infinity Edge helps soften your mid-game weakness, but at the cost of stalling the power spike you get from Infinity Edge.

Either way, once you get one of these items, you should probably upgrade your boots. Berserker's Greaves are your best option unless the enemy team is very heavy on magic damage or crowd control, in which case you may want to consider Mercury's Treads.

This is where Tristana has trouble. You probably outrange the enemy AD carry, but unless you have several more kills than they do they're probably stronger, so trying to duel them is not a great idea. If your team is grouping up, try to stick with them, grabbing minions where you can; if you see that a lane is pushing towards your side of the map, it may be a good idea to go farm it out to get the extra gold flowing. Play cautiously here; in this phase of the game you probably should just be aiming to survive and, where possible, farm. Kills are not your priority unless you're ahead already.

At this point in the game, you should probably be aiming for a Phantom Dancer; the attack speed and critical chance are extremely good for AD carries, since these scale multiplicatively with each other and with attack damage. After that, assess the situation before deciding on your next buy. If the enemy team has a lot of armor, pick up a Last Whisper; if they don't have a lot of armor but do have a lot of health, pick up a Blade of the Ruined King if you didn't already; if they have neither of the above, consider a Bloodthirster (or Infinity Edge if you got Bloodthirster earlier). There are a few other situational items here - for instance, if you're against a Malzahar getting a Quicksilver Sash here might not be a bad idea - but these should be the most common cases.

If you've made it this far, you should be good to go. By this point you likely either outdamage or outrange the enemy AD carry (unless it's Kog'Maw or Twitch, who you still beat in safety). Keep getting creeps if they're available and your team doesn't need you, but at this point you can probably win teamfights if your team knows what they're doing. Generally speaking, your team should be constantly sticking together at this point. When you fight, make sure to not let the enemies get to you! If they jump you, use Buster Shot to force them away; if they're still on you, use Rocket Jump (and Flash, if necessary) to open the distance between and keep hammering at them until you and your team can kill them or force them off of you. If you get stunned, snared, or some kind of major attack speed slow (like Nasus's Wither), you should probably Cleanse or use Quicksilver Sash/Mercurial Scimitar to get rid of it immediately if that's possible. Hit the targets that you can; don't go deep just to target the enemy squishies if that means their tanks can kill you. If their tanks are what's available to hit without you dying, hit the tanks, then make your way through them.

If you can help it, it is probably not a good idea to go to the bottom lane, especially without your team. You are probably your team's primary damage source. If the enemy team sees that you are bot, they might try to take Baron, and they have a good shot at taking it and/or winning the resulting fight without you there. If your team can push bottom lane to the point that they either stop you or lose an inhibitor, then bot lane can be a good place to push, but it's probably the riskiest place on the map to show your face in the later parts of the game.

If you didn't already pick up a Last Whisper, that's almost certainly something you should grab at this point. Your build should look something like: boots, Infinity Edge, Phantom Dancer, Bloodthirster/Blade of the Ruined King, Last Whisper. The last slot is usually best used on a defensive item: Guardian Angel and Warmog's Armor are both solid choices, but Quicksilver Sash into Mercurial Scimitar is not a bad idea if enemy crowd control is still a problem. If you get the defensive item and still have gold, you can sell your boots for a Zephyr, then start buying Elixirs. At that point though, you should probably let your team have the minion kills where possible, since you have no more use for them.

For the most part, Tristana will be outscaled by the enemy AD carry in the mid-game but will outscale them come late-game. Also, Tristana tends to do well against sustain supports, but not as well against CC or poke-heavy supports. Here are a few important matchups to keep in mind.

You do not gain a range advantage over Caitlyn until level 13, so be mindful of her poke. If you and your support can all-in her you have a good chance at a kill, since her escape isn't that good, but make sure she doesn't poke you down first. Dodge her Piltover Peacemaker, don't try to jump over her traps (it won't end well for you) and be careful not to get poked down too hard, and you should do fine.

Draven is one of the strongest lane bullies in the bottom lane. Most AD carries simply cannot trade with him in lane, and Tristana is no exception. Draven hits HARD. Be very careful not to let him deal much damage to you; you're probably going to have to farm under your tower and you're likely to need help from your jungler. This is a lane you aren't likely to win, but you'll be much stronger come late-game. Just make sure you get there!

Miss Fortune usually has a hard time against Tristana. Due to Miss Fortune's average range, you can harass her just by last-hitting minions near her, since she'll almost have to be standing near them to farm. You outrange her at level 2, so you should be able to hit her with Explosive Shot fairly often and not take too much damage in return. She has decent poke, but your all-in should be better and you can avoid her ult either by dodging it with W or cancelling it with R.

In lane, this matchup is roughly even; you both have good poke and mobility. Corki's mid-game is much, much better than yours though; once he gets his Trinity Force, you probably don't want to mess with him much anymore. He'll out-poke you and still have about the same burst as you do, maybe a bit better. You'll outscale him very, very hard later, but be careful not to give up kills to him during the mid-game when he's stronger than you.

Don't let her low range fool you, Sivir is generally a strong pick against Tristana. The cooldown on her spell shield is around the same as your Explosive Shot cooldown, so she can just use that ability to give herself more mana to poke you down with Boomerang Blade and Ricochet. She'll probably out-poke you, and once she hits 6 she can usually all-in better than you can, especially since On the Hunt makes escape difficult, so be very careful how you play this. Again, you'll outscale her hilariously hard later on, but she can wreck you through the early and mid-game.

Lucian is strong in the early and mid-game, but not as powerful late. He's almost certainly going to outdamage you if you try to trade with him, since his passive effectively makes his next attack do 1.5x damage after each ability use. You're also likely to have a hard time going all-in against him, since his E, Relentless Pursuit, is a dash that removes slows. Hit Explosive Shot on him when you can, but be careful not to let him hit you too often.

Jinx is an interesting case. She gains your main late-game benefits - 700ish range and a large attack speed increase - much earlier than you do, but she only has one at a time. Her lane control is probably better than yours, since she can also do damage to multiple creeps with one hit, but hers is a toggled ability instead of forced. She also has very good poke and a snare, plus her ult has an execute component to it. Until much later in the game, she'll consistently either outrange you or have much higher attack speed than you do, so I'd advise against prolonged damage trades unless you have something tipping the balance in your favor, like a numbers advantage or CC from your support. Once you hit the late game though, you should have the advantage provided you can keep her at range, where she doesn't gain her attack speed boost. If your support lands good crowd control on her though, don't be afraid to go all-in, since Jinx doesn't have any natural escapes.

Tristana can work with pretty much any support, but tends to do better with aggressive supports so that she can capitalize on her strong early game. The more poke and/or crowd control the support has, the better they are likely to do with Tristana. Thresh, Leona, and Annie are very strong supports in general and they work well with Tristana, but you can work with pretty much anyone.

If you have a Thresh or a Blitzcrank then you can wait until they land their hook, then jump over the enemy champion and Buster Shot them even further back for an almost guaranteed kill; that much displacement is almost impossible to escape from without taking too much damage to survive.

Tristana can be played as an AP carry with a good deal of success, as three of her abilities (Rocket Jump, Explosive Shot, and Buster Shot) scale very well with Ability Power. On top of that, Rocket Jump resets on kills and assists, giving Tristana an easy spammable damage tool once enemies start to die.

As AP Tristana, you'll want to ignore Rapid Fire as much as possible; it just doesn't do you much good. Rabadon's Deathcap is a good investment, as is some cooldown reduction. AP Tristana's range is just as good as AD Tristana's, so a Lich Bane can be used to help you capitalize on that.

If you choose to play AP Tristana, you'll probably still want a 21/9/0 mastery page, except you'll want to take the right side of the Offense tree instead of the left side. As for runes, it's often best to take magic penetration marks, armor seals, either ability power or scaling magic resistance glyphs (depending on your opponent) and ability power quintessences.

I am not very experienced with AP Tristana though, so take all of my advice here with a grain of salt!